Embolic protection devices

ABSTRACT

An embolic protection device for use in a blood vessel when an interventional procedure is being performed in a stenosed or occluded region to capture any embolic material which may be created and released into the bloodstream during the procedure. The device includes a filtering assembly having a self-expanding strut assembly and a filter element attached thereto. In one embodiment, the filtering assembly is attached to the distal end of a guide wire and is deployed within the patient&#39;s vasculature as the guide wire is manipulated into the area of treatment. A restraining sheath placed over the filtering assembly in a coaxial arrangement maintains the filtering assembly in its collapsed position until it is ready to be deployed by the physician. Thereafter, the sheath can be retracted to expose the filtering assembly which will then self-expand within the patient&#39;s vasculature. Interventional devices can be delivered over the guide wire and any embolic debris created during the interventional procedure and released into the blood stream will enter the filtering assembly and be captured therein. Other embodiments include filtering assemblies attached to an outer tubular member and inner shaft member which apply axial force to the distal ends of the assembly to either expand or contract the struts as needed.

[0001] This application is a divisional of application Ser. No.09/490,319 filed Jan. 24, 2000 which is a continuation-in-part ofapplication Ser. No. 09/476,159 filed Dec. 30, 1999, which is assignedto the same Assignee as the present application.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to filtering devices andsystems which can be used when an interventional procedure is beingperformed in a stenosed or occluded region of a blood vessel to captureembolic material that may be created and released into the bloodstreamduring the procedure. The embolic filtering devices and systems of thepresent invention are particularly useful when performing balloonangioplasty, stenting procedures, laser angioplasty or atherectomy incritical vessels, particularly in vessels such as the carotid arteries,where the release of embolic debris into the bloodstream can occlude theflow of oxygenated blood to the brain or other vital organs, which cancause devastating consequences to the patient. While the embolicprotection devices and systems of the present invention are particularlyuseful in carotid procedures, the inventions can be used in conjunctionwith any vascular interventional procedure in which there is an embolicrisk.

[0003] A variety of non-surgical interventional procedures have beendeveloped over the years for opening stenosed or occluded blood vesselsin a patient caused by the build up of plaque or other substances on thewall of the blood vessel. Such procedures usually involve thepercutaneous introduction of the interventional device into the lumen ofthe artery, usually through a catheter. In typical carotid PTAprocedures, a guiding catheter or sheath is percutaneously introducedinto the cardiovascular system of a patient through the femoral arteryand advanced through the vasculature until the distal end of the guidingcatheter is in the common carotid artery. A guide wire and a dilatationcatheter having a balloon on the distal end are introduced through theguiding catheter with the guide wire sliding within the dilatationcatheter. The guide wire is first advanced out of the guiding catheterinto the patient's carotid vasculature and is directed across thearterial lesion. The dilatation catheter is subsequently advanced overthe previously advanced guide wire until the dilatation balloon isproperly positioned across the arterial lesion. Once in position acrossthe lesion, the expandable balloon is inflated to a predetermined sizewith a radiopaque liquid at relatively high pressures to radiallycompress the atherosclerotic plaque of the lesion against the inside ofthe artery wall and thereby dilate the lumen of the artery. The balloonis then deflated to a small profile so that the dilatation catheter canbe withdrawn from the patient's vasculature and the blood flow resumedthrough the dilated artery. As should be appreciated by those skilled inthe art, while the above-described procedure is typical, it is not theonly method used in angioplasty.

[0004] Another procedure is laser angioplasty which utilizes a laser toablate the stenosis by super heating and vaporizing the depositedplaque. Atherectomy is yet another method of treating a stenosed bloodvessel in which cutting blades are rotated to shave the deposited plaquefrom the arterial wall. A vacuum catheter is usually used to capture theshaved plaque or thrombus from the blood stream during this procedure.

[0005] In the procedures of the kind referenced above, abrupt reclosuremay occur or restenosis of the artery may develop over time, which mayrequire another angioplasty procedure, a surgical bypass operation, orsome other method of repairing or strengthening the area. To reduce thelikelihood of the occurrence of abrupt reclosure and to strengthen thearea, a physician can implant an intravascular prosthesis formaintaining vascular patency, commonly known as a stent, inside theartery across the lesion. The stent is crimped tightly onto the balloonportion of the catheter and transported in its delivery diameter throughthe patient's vasculature. At the deployment site, the stent is expandedto a larger diameter, often by inflating the balloon portion of thecatheter.

[0006] Prior art stents typically fall into two general categories ofconstruction. The first type of stent is expandable upon application ofa controlled force, as described above, through the inflation of theballoon portion of a dilatation catheter which, upon inflation of theballoon or other expansion means, expands the compressed stent to alarger diameter to be left in place within the artery at the targetsite. The second type of stent is a self-expanding stent formed from,for example, shape memory metals or super-elastic nickel-titanum (NiTi)alloys, which will automatically expand from a collapsed state when thestent is advanced out of the distal end of the delivery catheter intothe body lumen. Such stents manufactured from expandable heat sensitivematerials allow for phase transformations of the material to occur,resulting in the expansion and contraction of the stent.

[0007] The above non-surgical interventional procedures, whensuccessful, avoid the necessity of major surgical operations. However,there is one common problem which can become associated with all ofthese non-surgical procedures, namely, the potential release of embolicdebris into the bloodstream that can occlude distal vasculature andcause significant health problems to the patient. For example, duringdeployment of a stent, it is possible that the metal struts of the stentcan cut into the stenosis and shear off pieces of plaque which becomeembolic debris that can travel downstream and lodge somewhere in thepatient's vascular system. Pieces of plaque material can sometimesdislodge from the stenosis during a balloon angioplasty procedure andbecome released into the bloodstream. Additionally, while completevaporization of plaque is the intended goal during a laser angioplastyprocedure, quite often particles are not fully vaporized and thus enterthe bloodstream. Likewise, not all of the emboli created during anatherectomy procedure may be drawn into the vacuum catheter and, as aresult, enter the bloodstream as well.

[0008] When any of the above-described procedures are performed in thecarotid or arteries, the release of emboli into the circulatory systemcan be extremely dangerous and sometimes fatal to the patient. Debristhat is carried by the bloodstream to distal vessels of the brain cancause these cerebral vessels to occlude, resulting in a stroke, and insome cases, death. Therefore, although cerebral percutaneoustransluminal angioplasty has been performed in the past, the number ofprocedures performed has been limited due to the justifiable fear ofcausing an embolic stroke should embolic debris enter the bloodstreamand block vital downstream blood passages.

[0009] Medical devices have been developed to attempt to deal with theproblem created when debris or fragments enter the circulatory systemfollowing vessel treatment utilizing any one of the above-identifiedprocedures. One approach which has been attempted is the cutting of anydebris into minute sizes which pose little chance of becoming occludedin major vessels within the patient's vasculature. However, it is oftendifficult to control the size of the fragments which are formed, and thepotential risk of vessel occlusion still exists, making such a procedurein the carotid arteries a high-risk proposition.

[0010] Other techniques which have been developed to address the problemof removing embolic debris include the use of catheters with a vacuumsource which provides temporary suction to remove embolic debris fromthe bloodstream. However, as mentioned above, there have beencomplications with such systems since the vacuum catheter may not alwaysremove all of the embolic material from the bloodstream, and a powerfulsuction could cause problems to the patient's vasculature. Othertechniques which have had some limited success include the placement ofa filter or trap downstream from the treatment site to capture embolicdebris before it reaches the smaller blood vessels downstream. However,there have been problems associated with filtering systems, particularlyduring the expansion and collapsing of the filter within the bodyvessel. If the filtering device does not have a suitable mechanism forclosing the filter, there is a possibility that trapped embolic debriscan backflow through the inlet opening of the filter and enter theblood-stream as the filtering system is being collapsed and removed fromthe patient. In such a case, the act of collapsing the filter device mayactually squeeze trapped embolic material through the opening of thefilter and into the bloodstream.

[0011] Many of the prior art filters which can be expanded within ablood vessel are attached to the distal end of a guide wire or guidewire-like tubing which allows the filtering device to be placed in thepatient's vasculature when the guide wire is manipulated in place. Oncethe guide wire is in proper position in the vasculature, the embolicfilter can be deployed within the vessel to capture embolic debris. Theguide wire can then be used by the physician to deliver interventionaldevices, such as a balloon angioplasty dilatation catheter or a stent,into the area of treatment. When a combination of embolic filter andguide wire is utilized, the proximal end of a guide wire can be rotatedby the physician, usually unintentionally, when the interventionaldevice is being delivered over the guide wire in an over-the-wirefashion. If the embolic filter is rigidly affixed to the distal end ofthe guide wire, and the proximal end of the guide wire is twisted orrotated, that rotation will be translated along the length of the guidewire to the embolic filter, which can cause the filter to rotate or movewithin the vessel and possibly cause trauma to the vessel wall.Additionally, it is possible for the physician to accidentally collapseor displace the deployed filter should the guide wire twist when theinterventional device is being delivered over the guide wire. Moreover,a shockwave (vibratory motion) caused by the exchange of the deliverycatheter or interventional devices along the guide wire can ajar thedeployed filtering device and can possibly result in trauma to the bloodvessel. These types of occurrences during the interventional procedureare undesirable since they can cause trauma to the vessel which isdetrimental to the patient's health and/or cause the deployed filter tobe displaced within the vessel which may result in some embolic debrisflowing past the filter into the downstream vessels.

[0012] What has been needed is a reliable filtering device and systemfor use when treating stenosis in blood vessels which helps prevent therisk associated when embolic debris that can cause blockage in vesselsat downstream locations is released into the bloodstream. The deviceshould be capable of filtering any embolic debris which may be releasedinto the bloodstream during the treatment and safely contain the debrisuntil the filtering device is to be collapsed and removed from thepatient's vasculature. The device should be relatively easy for aphysician to use and should provide a failsafe filtering device whichcaptures and removes any embolic debris from the bloodstream. Moreover,such a device should be relatively easy to deploy and remove from thepatient's vasculature. The inventions disclosed herein satisfy these andother needs.

SUMMARY OF INVENTION

[0013] The present invention provides a number of filtering devices andsystems for capturing embolic debris in a blood vessel created duringthe performance of a therapeutic interventional procedure, such as aballoon angioplasty or stenting procedure, in order to prevent theembolic debris from blocking blood vessels downstream from theinterventional site. The devices and systems of the present inventionare particularly useful while performing an interventional procedure incritical arteries, such as the carotid arteries, in which vitaldownstream blood vessels can easily become blocked with embolic debris,including the main blood vessels leading to the brain. When used incarotid procedures, the present invention minimizes the potential for astroke occurring during the procedure. As a result, the presentinvention provides the physician with a higher degree of confidence thatembolic debris is being properly collected and removed from thepatient's vasculature during the interventional procedure.

[0014] An embolic protection device and system made in accordance withthe present invention includes an expandable filtering assembly which isaffixed to the distal end of a tubular shaft member, such as a guidewire. The filtering assembly includes an expandable strut assembly madefrom a self-expanding material, such as nickel-titanium (NiTi) alloy orspring steel, and includes a number of outwardly extending struts whichare capable of self-expanding from a contracted or collapsed position toan expanded or deployed position within the patient's vasculature. Afilter element made from an embolic capturing media is attached to theexpandable strut assembly and moves from the collapsed position to theexpanded position via the movement of the expandable struts. Thisexpandable strut assembly is affixed to the guide wire in such a mannerthat the entire filtering assembly rotates or “spins” freely on theguide wire to prevent the filtering assembly from being rotated afterbeing deployed within the patient's vasculature. In this manner, anyaccidental or intentional rotation of the proximal end of the guide wireis not translated to the deployed filtering assembly, which will remainstationary within the patient's vasculature and, as such, the threat oftrauma to the vessel wall and displacement of the filter caused by therotation and/or manipulation of the guide wire can be virtuallyeliminated.

[0015] The expandable struts of the strut assembly can be biased toremain in their expanded position until an external force placed on thestruts to collapse and maintain the struts in their contracted orcollapsed position is removed. This is done through the use of arestraining sheath which is placed over the filtering assembly in acoaxial fashion to maintain the strut assembly in its collapsedposition. The composite guide wire and filtering assembly, with therestraining sheath placed over the filtering assembly, can then beplaced into the patient's vasculature. Once the physician properlymanipulates the guide wire into the target area, the restraining sheathcan be retracted off of the expandable strut assembly to deploy thestruts into their expanded position. This can be easily performed by thephysician by simply retracting the proximal end of the restrainingsheath (which is located outside of the patient) along the guide wire.Once the restraining sheath is retracted, the self-expanding propertiesof the strut assembly cause the struts to move radially outward awayfrom the guide wire to contact the wall of the blood vessel. Again, asthe struts expand radially, so does the filter element which will now bein place to collect any embolic debris that may be released into thebloodstream as the physician performs the interventional procedure. Thefilter sub-assembly could be bonded to the core wire at both distal andproximal ends of the embolic protection device. The core wire could bemade from stainless steel or shaped memory biocompatible materials. Theguide wire with the embolic protection device could be loaded into adelivery sheath. The delivery sheath could be torqued, steering thedevice into the intended vessel site.

[0016] The filtering assembly can be rotatably affixed to the guide wireby rotatably attaching the proximal end of the filtering assembly to theguide wire. The distal end of the strut assembly can move longitudinallyalong the guide wire and is also rotatable on the guide wire as well.This allows the strut assembly to move between its collapsed andexpanded positions while still allowing the entire filtering assembly tofreely rotate or “spin” about the guide wire. This attachment of theproximal end of the strut assembly to the guide wire allows therestraining sheath to be retracted from the filtering assembly andpermits a recovery sheath to be placed over the expanded strut assemblyto move the strut assembly back to the collapsed position when theembolic protection device is to be removed from the patient'svasculature.

[0017] The filtering assembly also may include a dampening element ormember which is utilized to absorb some of the shockwave (vibratorymotion) that may be transmitted along the length of the guide wireduring the handling of the guide wire by the physician. Since a suddenshock to the filtering assembly can cause the filter to scrape the wallof the blood vessel or become displaced in the vessel, the dampeningmember acts much like a “shock absorber” to absorb some of the shock andprevent the transmission of the shock force to the filtering assembly.This shock can be produced via a number of way, for example, through theexchange of interventional devices along the guide wire. Also, when therestraining sheath is removed from the filtering assembly, a shockwavecan be created if the self-expanding struts open too quickly. As aresult of utilizing the dampening member, shock and trauma to thepatient's vasculature are minimized and the chances of displacing thefilter are virtually eliminated. In one particular embodiment of thedampening member, a helical spring is formed on the proximal end of theexpandable strut assembly to provide dampening to the assembly. Othermethods of obtaining dampening can be utilized, such as attaching aspring or elastomeric member to the strut assembly.

[0018] The expandable strut assembly made in accordance with the presentinvention may be made from a length of tubing (also known as a“hypotube”) made from a shape memory alloy or other self-deployingmaterial. Stainless steel or other biocompatible metals or polymers canbe utilized to form the struts of the assembly. One preferable materialis a shape memory alloy such as nickel-titanium (NiTi). The individualstruts of the expandable strut assembly are formed on the length ofhypotube by selectively removing material from the tubing to form theparticular size and shape of the strut. For example, the wall of thehypotube can be laser cut with slots to form the individual struts.Small tabs can also be lazed into the tubing along the strut which canbe used to hold the filter member in place. By selectively removingportions of the hypotube by a high precision laser, similar to lasersutilized in the manufacturer of stents, one can achieve a very preciseand well defined strut shape and length. In one particular embodiment ofthe present invention, the pattern of the material to be removed fromthe hypotubing can be a repeating diamond-shaped which creates a strutpattern in the form of two inverted triangles meshed together. Thisparticular strut pattern provides greater strength along the strut whereit would have a tendency to break or become weakened. Such a strutpattern also provides for a more natural bending position for eachstrut, allowing the expandable strut assembly to open and close moreuniformly. In one particular pattern, the strut pattern requires theremoval of a repeating truncated diamond pattern by laser or other meansto create the shape of the strut. In this particular pattern, each struthas a relatively straight center section formed between two invertedtriangles, somewhat similar to the strut pattern described above. Thisparticular strut pattern provides an expanded center section whichallows the struts to expand to a greater volume, which helps in thecapture of emboli by allowing a larger filter to be placed on the strutassembly. The center section located between the two inverted trianglealso provides a sufficient working area to attach the filter elementonto the strut assembly. These same features can be accomplished bycurved sections which have a reduced width in the center section.

[0019] The embolic protection device may also include a filteringassembly with a strut assembly which is not self-expanding, but utilizesthe application of a force on the proximal and distal ends of the strutassembly to deploy and collapsed the assembly. In this particular formof the invention, the embolic protection device includes an inner shaftmember and an outer tubular member which is coaxially disposed over theinner shaft member. The distal end of the expandable strut assembly canbe attached to the inner shaft member with the proximal end of the strutassembly being attached to the distal end of the outer tubular member.When there is relative movement between the inner shaft member and outertubular member, a force is created which is imparted to the expandablestrut assembly to cause the struts to either contract or expand. Forexample, in the embodiment described above, when the outer tubularmember and inner shaft member are moved relative to each other toproduce an inward force acting on the proximal and distal ends of thestrut assembly, the force causes the expandable struts to move from thecollapsed position into the expanded position. Thereafter, when thestrut assembly is to be collapsed, the outer tubular member and innershaft member can be moved relative to each other to create an outwardforce acting on the proximal and distal end of the strut assembly tocause the expanded struts to move back to their collapsed position. Aphysician easily can manipulate the proximal ends of the inner shaftmember and outer tubular member to deploy and collapse the filteringassembly as needed. The filtering assembly could be self-expanding withthe movement of the inner and outer members providing the means forexpanding and collapsing the assembly without the need for an outersheath.

[0020] The inner shaft member can be a guide wire which can be utilizedto move the filtering assembly directly into position downstream fromthe lesion for capturing any embolic debris which may be released intothe bloodstream. The inner shaft member could also be a elongatedtubular member which has an inner lumen that can track along a guidewire once the guide wire has been maneuvered into position into thepatient's vasculature. The entire embolic protection device can then bedelivered to the desired location over the guide wire usingover-the-wire techniques.

[0021] The filtering element utilized in conjunction with the embolicprotection device can take on many different preferred forms as aredisclosed herein. In one particular embodiment, the filter includes aproximal cone section which expands to the diameter of the artery inwhich the embolic protection device is to be deployed. This proximalcone section funnels blood flow and embolic debris into a main orcentral filter located distal to the proximal cone section. Thisproximal cone may or may not provide filtering itself. Its primaryfunction is flow direction and its ability to collapse and expand withthe expandable struts of the strut assembly. A main or central filtermay comprise an elongated tubular shaped member is located distal to theproximal cone section. It is integral with the distal end of theproximal cone section and provides a large filtering area that acts as astorage reservoir for holding embolic material. Ideally, it is sized sothat it receives any and all of the embolic material which it is to befiltered by the embolic protection device. It includes a number ofperfusion openings which allow blood to pass through but retain embolicmaterial. The central filter may not be collapsible or expandable, butrather may be made somewhat rigid and has an outer diameter large enoughto provide a storage reservoir for holding embolic material yet can bewithdrawn and delivered through the particular guiding catheter utilizedto deploy the embolic protection device into the patient's vasculature.The central filter also could be made from collapsible material, butshould have an outer diameter which is large enough to provide anadequate storage reservoir yet can be withdrawn through the guidingcatheter as well. Although this central filter may have a substantiallyfixed diameter, it can also be tapered and should have an outer diametersmall enough to fit through the inner diameter of the specific guidingcatheter utilized to deploy the device.

[0022] As with all of the filter elements made in accordance with thepresent invention, the material which can be utilized includes a varietyof materials such as polymeric material which is foldable and recoverselastically to aid in the capture of the emboli trapped in the filter.Other suitable materials include braided or woven bio-compatiblematerial which can significantly filter the desired size of the embolicdebris to be captured by the filter. The filter can be formed by blowinga suitable material into the proposed shape and then cutting offunwanted portions. The perfusion openings can be drilled into thematerial using a laser, such as an excimer laser, or by mechanicallydrilling and punching the openings to the desired size and shape. Laserdrilling of the holes provides accuracy, quickness and the ability todrill complex hole shapes, circles, ovals and slots. Alternatively, thecentral filter can be made from the same or different material from theproximal cone portion and can be welded or bonded to create an integralunit.

[0023] In one particular filter made in accordance with the presentinvention, the proximal cone includes advantageous features which helpprevent the filter from slipping off the expandable strut assembly.These features also help to prevent trapped embolic debris from beingsqueezed out of the filter as the filter is being collapsed for removalfrom the patient's vasculature. The filter may include, for example, aset of restraining straps designed to be attached to each of theproximal ends of the struts to help secure the filter onto the strutassembly. These straps can include tabs which can be wrapped around eachof the struts and permanently affixed thereto utilizing a suitableadhesive. The proximal cone section of the filter may also include anumber of indented flaps which cooperate to close off the inlet openingof the central filter. These indented flaps are formed on the proximalcone and move into position to cover the opening of the central filterwhen the proximal cone section is collapsed by the strut assembly.Therefore, the possibility that any embolic debris trapped within thedeep reservoir of the central filter will be discharged through theinlet opening is greatly diminished since the opening will be closed offby these indented flaps. Likewise, the proximal cone section of thefilter can also include inwardly inverting flaps located near the inletopening of the proximal cone section which cooperate to close off thelarge inlet opening of the proximal cone section whenever the strutassembly is collapsed. These elements help to prevent accidental leakageof trapped embolic debris whenever the filtering assembly is collapsedfor removal from the patient.

[0024] These and other advantages of the present invention will becomemore apparent from the following detailed description of the invention,when taken in conjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is an elevational view, partially in cross section, of anembolic protection device embodying features of the present inventionshowing the expandable filtering assembly in its collapsed positionwithin a restraining sheath and disposed within a vessel.

[0026]FIG. 2 is an elevational view, partially in cross section, similarto that shown in FIG. 1, wherein the expandable filtering assembly is inits expanded position within the vessel.

[0027]FIG. 3 is a perspective view of the strut assembly which formspart of the filtering assembly of the present invention as shown in itscollapsed position.

[0028]FIG. 4 is a plan view of a flattened section of the expandablestrut assembly shown in FIG. 3 which illustrates one particular strutpattern for the expandable strut assembly.

[0029]FIG. 5 is a perspective view of another embodiment of anexpandable strut assembly which forms part of the filtering assembly ofthe present invention in its collapsed position.

[0030]FIG. 6 is a plan view of a flattened section of the expandablestrut assembly of FIG. 5 which shows an alternative strut pattern forthe expandable strut assembly.

[0031]FIG. 7 is an elevational view, partially in cross section, of theproximal end of the expandable strut assembly of FIG. 2 as it isrotatably attached to the guide wire.

[0032]FIG. 8 is an elevational view, partially in section andfragmented, showing the distal end of the filtering assembly of FIG. 2as it is slidably mounted on the guide wire.

[0033]FIG. 9 is a perspective view of another embodiment of an embolicprotection device made in accordance with the present invention.

[0034]FIG. 10 is a elevational view of the various components making upthe embolic protection device of FIG. 9.

[0035]FIG. 11 is an elevational view of the embolic protection device ofFIG. 9 in its expanded position.

[0036]FIG. 12 is an end view of the filter element of the embolicprotective device of FIG. 11 taken along lines 12-12.

[0037]FIG. 13 is an end view of the filtering element of FIG. 12 whichshows the retaining tabs of the filter prior to being wrapped around thestruts of the expandable strut assembly to help retain the filer elementon the strut assembly.

[0038]FIG. 14 is an end view, similar to that shown in FIG. 12, ofanother embodiment of the filter element of the embolic protectiondevice which shows an alternative embodiment of retaining tabs andstructural elements that can be used to help retain the filter elementon the strut assembly.

[0039]FIG. 15 is an end view of the filter element of FIG. 14, showingthe retaining tabs of the filter element prior to being wrapped aroundthe struts of the expandable strut assembly to help retain the filterelement on the strut assembly.

[0040]FIG. 16 is a cross sectional view of the central filter of thefiltering device of FIG. 11 taken along lines 16-16.

[0041]FIG. 17 is an elevational view, partially in cross-section andfragmented, of the embolic protection device of FIG. 11 showing theindented flaps of the proximal cone section in the expanded position.

[0042]FIG. 18 is an elevational view, partially in cross-section andfragmented, showing the indented flaps of the proximal cone section inthe collapsed position which causes the indented flaps to close theinlet opening of the central filter of the device.

[0043]FIG. 19 is a perspective view of an embolic protection device madein accordance with the present invention which includes inverted flapswhich help close the inlet opening of the proximal cone section of thefilter element when the device is collapsed.

[0044]FIG. 20 is an elevational view, partially in cross-section andfragmented, of the embolic protection device of FIG. 19 showing theproximal cone section and inverted flaps in an expanded position.

[0045]FIG. 21 is an elevational view, partially in cross-section andfragmented, of the embolic protection device of FIG. 19 wherein theproximal cone section is collapsed which causes the inverted flaps toclose off the inlet opening of the proximal cone section of the filterelement.

[0046]FIG. 22 is a perspective view of an alternative embodiment of afilter element made in accordance with the present invention.

[0047]FIG. 23 is an elevational view of the various components whichmake up another embodiment of an embolic protection device made inaccordance with the present invention.

[0048]FIG. 24 is an elevational view depicting the embolic protectiondevice of FIG. 23 in the expanded position.

[0049]FIG. 25 is an elevational view of the various components whichmake up another embodiment of an embolic protection device made inaccordance with the present invention.

[0050]FIG. 26 is an elevated view depicting the embolic protectiondevice of FIG. 25 in the expanded position.

[0051]FIG. 27 is an elevational view, partially in section, depictingthe embolic protection device of FIG. 25 in a collapsed position anddisposed within a vessel.

[0052]FIG. 28 is an elevational view, partially in section, similar tothat shown in FIG. 27, wherein the embolic protection device is expandedwithin the vessel.

[0053]FIG. 29 is another embodiment of an embolic protection device madein accordance with the present invention.

[0054]FIG. 30 is an elevational view, partially in section, of theembolic protection device of FIG. 29 in its expanded condition within avessel.

[0055]FIG. 31 is another embodiment of an embolic filtering device madein accordance with the present invention.

[0056]FIG. 32 is an elevational view, partially in section, of theembolic filtering device of FIG. 31 in its expanded condition anddisposed within a vessel.

[0057]FIG. 33 is an elevational view of the various components making upanother embodiment of an embolic protection device made in accordancewith the present invention.

[0058]FIG. 34 is an elevational view depicting the embolic protectiondevice of FIG. 33 in its expanded position.

[0059]FIG. 35 is an elevational view depicting the embolic protectiondevice of FIG. 34 in its collapsed position.

[0060]FIG. 36 is an elevational view, partially in section, of analternative embodiment of an embolic protection device similar to thatshown in FIG. 34.

[0061]FIG. 37 is an elevational view of two deployment members whichmove the struts of the strut assembly into the expanded or collapsedpositions.

[0062]FIG. 38 is an end view of the filtering assembly of FIG. 34 takenalong lines 38-38.

[0063]FIG. 39A is an elevational view depicting an alternative strutassembly made in accordance with the present invention which allows theassembly to be collapsed to a lower profile.

[0064]FIG. 39B is an elevational view depicting an alternative strutassembly made in accordance with the present invention which allows theassembly to be collapsed to a lower profile.

[0065]FIG. 40 is an expanded side view showing the arrangement of strutson the strut assembly of FIG. 39.

[0066]FIG. 41 is an alternative embodiment of a filter assembly with analternative filter element made in accordance with the presentinvention.

[0067]FIG. 42 is an enlarged side view of the filter element of thefiltering assembly of FIG. 41.

[0068]FIG. 43 is an elevational view of a proximal locking mechanismwhich can be utilized in accordance with embodiments of the embolicprotection device made in accordance with the present invention.

[0069]FIG. 44 is an elevational view, partially in section, showing thebiasing spring of the locking mechanism of FIG. 39 which can maintainthe embolic protection device either in the collapsed or expandedposition.

[0070]FIG. 45 is an elevational view of the various components making upanother embodiment of an embolic protection device made in accordancewith the present invention.

[0071]FIG. 46 is an elevational view depicting the embolic protectiondevice of FIG. 45 in its expanded position.

[0072]FIG. 47 is an elevation view depicting the embolic protectiondevice of FIG. 46 as it is being moved into its collapsed position.

[0073]FIG. 48 is a cross-sectional view of the embolic protection deviceof FIG. 46.

[0074]FIG. 49 is an elevational view of another embodiment of theembolic protection device made in accordance with the present invention.

[0075]FIG. 50 is a cross-sectional view depicting the embolic protectiondevice of FIG. 49 in its expanded position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0076] Turning now to the drawings, in which like reference numeralsrepresent like or corresponding elements in the drawings, FIGS. 1 and 2illustrate an embolic protection device 10 incorporating features of thepresent invention. In the particular embodiment shown in FIGS. 1 and 2,the embolic protection device 10 comprises a filter assembly 12 whichincludes an expandable strut assembly 14 and a filter element 16. Thefilter assembly 12 is rotatably mounted on the distal end of anelongated tubular shaft, such as a guide wire 18. Additional detailsregarding particular structure and shape of the various elements makingup the filter assembly 12 are provided below.

[0077] The embolic protection device 10 is shown as it is placed withinan artery 20 or other blood vessel of the patient. This portion of theartery 20 has an area of treatment 22 in which atherosclerotic plaque 24has built up against the inside wall 26 of the artery 20. The filterassembly 12 is placed distal to, and downstream from, the area oftreatment 22 as is shown in FIGS. 1 and 2. Although not shown, a balloonangioplasty catheter can be introduced within the patient's vasculaturein a conventional SELDINGER technique through a guiding catheter (notshown). The guide wire 18 is disposed through the area of treatment andthe dilatation catheter can be advanced over the guide wire 18 withinthe artery 20 until the balloon portion is directly in the area oftreatment. The balloon of the dilatation catheter can be expanded,expanding the plaque 24 against the inside wall 26 of the artery 20 toexpand the artery and reduce the blockage in the vessel at the positionof the plaque 24. After the dilatation catheter is removed from thepatient's vasculature, a stent 25 (shown in FIG. 2) could also bedelivered to the area of treatment 22 using over-the-wire techniques tohelp hold and maintain this portion of the artery 20 and help preventrestenosis from occurring in the area of treatment. Any embolic debris27 which is created during the interventional procedure will be releasedinto the bloodstream and will enter the filtering assembly 12 locateddownstream from the area of treatment 22. Once the procedure iscompleted, the filtering assembly 12 is collapsed and removed from thepatient's vasculature, taking with it all embolic debris trapped withinthe filter element 16.

[0078] One particular form of the expandable strut assembly 14 is shownin FIGS. 1-4. As can be seen in these figures, the expandable strutassembly 14 includes a plurality of radially expandable struts 28 whichcan move from a compressed or collapsed position as shown in FIG. 1 toan expanded or deployed position shown in FIG. 2. FIG. 3 shows a lengthof tubing 30 which can be utilized to form this expandable strutassembly 14.

[0079] The expandable strut assembly 14 includes a proximal end 32 whichis rotatably attached to the guide wire 18 and a distal end 34 which isfree to slide longitudinally along the guide wire 18 and also can rotatethereabout. The distal end 34 moves longitudinally along the guide wirewhenever the struts move between the expanded and contrasted positions.The proximal end 32 includes a short tubular segment or sleeve 36 whichhas a coil spring formed therein which acts as a dampening member orelement 38. The function of this dampening element 38 will be explainedbelow. The distal end 34 of the tubing 30 also includes a short segmentor sleeve 40 which is slidably and rotatably disposed on the guide wire18.

[0080] Referring now to FIGS. 1, 2 and 7, the proximal end 32 of theexpandable strut assembly 14 is mounted between a tapered fitting 42located proximal to the dampening element 38 and a radiopaque markerband 44 located distal to the proximal end 32. The tapered end fitting42 and marker band 44 fix the proximal end 32 onto the guide wire 18 toprevent any longitudinal motion of the proximal end along the guide wirebut allow for rotation of the proximal end 32 and the filtering assembly12. This particular construction allows the expandable strut assembly torotate or “spin” freely about the guide wire. In this manner, thefiltering assembly 12 will remain stationary should the guide wire 18 berotated at its proximal end after the embolic detection device 10 hasbeen deployed within the patient's vasculature. This is just one way ofaffixing the expandable strut assembly 14 onto the guide wire 18 toallow it to spin or rotate on the guide wire 18. Other ways ofperforming this same function can be employed with the presentinvention.

[0081] The benefits of mounting the proximal end 32 of the expandablestrut assembly 14 to the guide wire 18 include the ability to preciselydeploy the filtering assembly 12 within the artery once the guide wire18 has been positioned in the patient's vasculature. Since the proximalend 32 cannot move longitudinally along the guide wire, the physiciancan be sure that the filtering element 12 will be placed exactly wherehe/she places it once the restraining sheath 46 is retracted to allowthe expandable struts to move into their expanded position.Additionally, since the proximal end 32 is affixed to the guide wire,any movement of the filtering element as the restraining sheath 46 isretracted should not occur. Since the expandable struts 28 can be madefrom self-expanding materials, there may be some stored energy in thefiltering assembly 12 as it is held in its collapsed position by therestraining sheath 46. As that restraining sheath 46 is retracted, therecan be a frictional build-up which can cause the strut assembly 14 tomove outward if the proximal end 32 were not affixed to the guide wire18. As a result, if the ends of the strut assembly 14 were not somehowfixed onto the guide wire, there could be a tendency of the filteringelement 12 to spring out of the restraining sheath 46 as it is beingretracted. As a result, the placement of the filtering element 12 willnot be as accurate since the physician will not be able to pre-determineif and how much the filtering assembly 12 would move as the restrainingsheath 46 is retracted.

[0082] The dampening element 38, which in this particular embodiment ofthe invention is shown as a helical coil formed on the proximal end 32of the strut assembly 14, helps to dampen any shockwaves (vibratorymotion) which may be transmitted along the guide wire 18, for example,when interventional devices are being delivered or exchanged over theguide wire in an over-the-wire fashion. Similarly, this dampeningelement 38 also helps dampen any shock forces which may result as therestraining sheath 46 is retracted to allow the radial expandable strutsto move into their expanded position as shown in FIG. 2. The helicalcoil can also act as an attachment method which helps retain guide wireflexibility. The dampening element 38 should somewhat also dampen shockwhich may be created as the recovery sheath 48 (FIG. 2) contacts thestruts to collapse the filter assembly 12 when the embolic protectiondevice is to be removed from the patient's vasculature. As a result,this dampening element 38 will absorb and dissipate forces which wouldotherwise act on the expanded filtering assembly 12 and could cause theassembly 12 to scrape the inside wall 26 of the artery 20 or otherwisecause trauma to the vessel. This dampening element 38 also helps preventdisplacement or misalignment of the filter element within the arterywhich may result from a sudden shock transmitted along the guide wire18.

[0083] The filter element 16 utilized in conjunction with this preferredembodiment of the invention includes a tapered or cone shaped section 50which has a plurality of openings 52 which allow the blood to flowthrough the filter 16 but captures emboli within the inside of the coneshaped section. The filter element 16 includes a short proximal section52 which is integral with the cone shaped section 50 and expands to asubstantially cylindrical shape when the struts 28 of the strut assembly14 are deployed. The inlet opening 51 allows any embolic debris 27 toenter the filter element 16 for capture. This short cylindrical section52 also serves as a suitable location where the filter element 16 can beadhesively or otherwise affixed to each strut 28 of the strut assembly14. The filter element 18 includes a short distal cylindrical section 54which is integral with the remaining sections of the filter and isattached to the sleeve segment 40 which forms the distal end 34 of theexpandable strut assembly 14. This distal cylindrical section 54 can beattached to the sleeve 40 using adhesives or other bonding techniques.

[0084] Referring again to FIG. 1, the filter assembly 12 is maintainedin its collapsed or compressed position through the use of a restrainingsheath 46 which contacts the struts 28 and filter elements 16 tomaintain the filtering assembly 12 collapsed. Although not shown, theguide wire and restraining sheath 46 have proximal ends which extendoutside the patient. The struts 28 can be manipulated into the expandedposition by retracting the restraining sheath 46 (via its proximal end)to expose the struts 28. Since the struts 28 are self expanding, theremoval of the restraining sheath 46 allows the struts 28 and filterelement 16 to move to the expanded position within the artery 20.

[0085] The guide wire 18 includes a small sphere 56 affixed theretowhich is beneficial during the delivery of the embolic protection device10 into the patient's vasculature. This sphere 56 is approximately aslarge as the inner diameter of the restraining sheath 46 and is utilizedas a “nosecone” to prevent possible “snow plowing” of the embolicprotection device as it is being delivered through the patient'sarteries. The sphere 56 is atraumatic and has a smooth surface to helpthe embolic protection device travel through the patient's vasculatureand cross lesions without causing the distal end of the restrainingsheath 46 to “dig” or “snow plow” into the wall of the arteries. Whenthe embolic protection device 10 is to be removed from the patient'svasculature, a recovery catheter 48 is utilized to collapse and recoverthe filter assembly 12. (FIG. 2). Generally, this recovery sheath 48 hasa slightly larger inner diameter than the restraining sheath 46 sincethe struts 28 are now deployed and may require some increased hoopstrength at the distal end 47 of the recovery sheath 48 to properly movethe strut assembly 14 back into its collapsed position. The collapse ofthe expandable strut assembly 14 can be accomplished by holding theguide wire 18 and moving the proximal end (not shown) of the recoverysheath 48 forward which will move the distal end 47 of the sheath 48over the struts 28. Alternatively, the recovery sheath 48 can be heldstationary while the proximal end of the guide wire is retracted back topull the entire filter assembly 12 into the sheath 48. Upon collapse ofthe filter assembly 12, any embolic debris generated and entering thebloodstream during the interventional procedure will remain trappedinside the filter element 16 and will be withdrawn from the bloodstreamwhen the embolic protection device 10 is removed from the patient'svasculature.

[0086] A radiopaque marker 58 located approximately at the longitudinalcenter of the expandable strut assembly 14 is also affixed to the guidewire 18 to provide the physician with a reference marker whenpositioning the device within the patient's artery 20.

[0087] The number of struts 28 formed on the expandable strut assembly14 can be any number which will provide sufficient expandability withinthe artery to properly deploy and maintain the filter element 16 inplace. In the embodiment shown in FIGS. 1 and 2, the expandable strutassembly has four self-expanding struts 28. Likewise, the particularsize and shape of each strut 28 can be varied without departing from thespirit and scope of the present invention. In this preferred embodiment,the strut pattern includes a first portion 60 having an invertedtriangular shape, a substantially straight center section 62, and asecond inverted triangular shaped section 64 which completes the strut.This particular strut pattern is preferred since the design providesgreater strength in regions of the strut where there would be a tendencyfor the strut to break or become weakened. These regions include thevery proximal and distal ends of each strut which are designed with awider base. This particular design also allows the composite strutassembly to open and close more uniformly which is beneficial especiallywhen collapsing the struts for removal from the patient. Additionally,the center section 62 allows the struts 28 to expand to a greatervolume, which allows a larger filter element to be placed on the strutassembly 14, if needed.

[0088] Referring now specifically to FIG. 4, a plan view of a rolled outflat sheet of the tubing 30 utilized to form the struts 28 is shown. Ascan be seen from FIG. 5, a particular design pattern is cut into wall ofthe tubing 30 in order to form each strut 28. In the case of theembodiment shown in FIG. 3, that pattern consists of a truncated diamondshape 65 which helps form the first section 60, the center section 62and the second section 64. By selectively removing portions of thetubing 30 through laser cutting or other suitable means, each particularstrut 28 can be made to a precise shape, width and length. Thistruncated diamond pattern 68 repeats as can be seen in FIG. 4 to provideuniform size to each of the struts 28 formed therein.

[0089] An alternative preferred embodiment of the expandable strutassembly 14 is shown in FIGS. 5 and 6. This particular strut assembly 14is similar to the one shown in FIGS. 3 and 4 except that there is nocenter section. The struts 68 shown in FIGS. 5 and 6 consist of a pairof inverted triangles which form a first section 70 and a second section72. The plan view of the flat sheet of the tubing 30 used to form thestrut assembly 14, as shown in FIG. 6, shows a repeating diamond pattern74 which is cut into the tubing to create each individual strut 28.Again, this particular pattern is preferred since greater strength isprovided near the proximal and distal ends of each strut where therewould be a tendency for breakage or a weakness of the strut. When theparticular pattern is cut into the tubing, whether it be the patternshown in FIGS. 3-4 or 5-6 or some other pattern, the sleeve 36 whichforms the proximal end 32 of the strut assembly 14 can thereafter besimilarly cut to create the helical coil which forms the damping element38 on the strut assembly 14.

[0090] Another embodiment of the present invention is shown in FIGS.9-11. As can be seen in FIG. 9, the embolic protection device 100includes a filter assembly 102 having an expandable strut assembly 104and a unique filter element 106. The particular strut assembly 104utilized with this embolic protection device 100 is similar to thestructure of the expandable strut assembly 14 shown in the previousembodiment. The filter element 106, which will be described in greaterdetail below, is utilized in its expanded position to collect anyembolic debris for removal from the blood stream of the patient.

[0091] The various elements making up this particular embodiment of theembolic protection device 100 are shown in FIG. 10. In this particularembodiment, the strut assembly 104 does not necessarily have to be madefrom a self-expanding material, as the strut assembly 14 disclosed inthe previous embodiment. Rather, it could be made from stainless steelor other materials which require the application of external axial forceon the proximal end 110 and distal end 112 of the strut assembly 104 tomove the struts 108 between the contracted and expanded positions. As isshown in FIGS. 10 and 11, the proximal end 110 of the assembly 104includes a short tubular or sleeve-like segment 114 and a similar distalsegment 116. The struts 108 are moved from a contracted to a deployedposition by imparting an inward axial force on the proximal end 110 anddistal end 112 of the strut assembly 104. This can be accomplished byfirst attaching the distal end 112 of the assembly 104 directly to theguide wire 118. The proximal end 110 of the strut assembly 104, canthen, in turn, be attached to an outer tubular member 120 which, alongwith the guide wire 118, has a proximal end which extends outside of thepatient. The proximal ends (not shown) of both the outer tubular member120 and the guide wire 118 can be manipulated by the physician to eitherimpart an inward axial force on the two ends 110 and 112 of the strutassembly 104 to move the struts 108 to the deploy position or can bemoved to impart an outward axial force on both ends 110 and 112 tocollapse the struts 108 back to their collapsed position.

[0092] The struts 108 of the strut assembly 104 can be made from a pieceof tubing (hypotube) in which select portions of the tubing are removedto form the particular size and shape of each strut. The strut assembly104 could also be made from a self-expanding material such asnickel-titanium (NiTi) if desired. The struts 108 would then be biasedinto either the collapsed or expanded position with the outer tubularmember 120 being used to move the proximal end 110 in order to expand orcontract the strut assembly 104, depending upon, of course, the mannerin which the expandable struts 108 are biased. Again, in the embodimentshown in FIG. 10, the struts 108 have a similar shape as the struts 28shown in the embodiment of FIGS. 1-4. This particular embodiment of anembolic protection device thus eliminates the need to utilize both arestraining sheath and recovery sheath which would be otherwise neededin order to deploy and contract the embolic protection device. Thisparticular design, however, does not allow for the filter assembly 102to rotate as freely along the guide wire 118 as does the previousembodiments, although there can be some rotation. However, the outertubular member 120 and guide wire 118 are utilized in a similar fashionby allowing interventional devices to be delivered over the outertubular member in an over-the-wire fashion after the embolic protectiondevice 110 is in place within the patient's vasculature.

[0093] It should be appreciated that the strut assembly 104 could alsobe made from a self-expanding material which maintains the struts 108biased in their expanded position. The outer tubular member 120 wouldstill be utilized in order to move the expanded struts 108 back intotheir collapsed position. The proximal ends of the outer tubular member120 and guide wire 118 can be attached to a simple locking mechanism 600(shown in FIGS. 39 and 40) which can be utilized to move the outertubular member relative to the guide wire for maintaining the strutassembly 104 in its collapsed position until ready to be deployed withinthe patient's vasculature. It should further be appreciated that theparticular embolic protection device 100 can also be modified toeliminate the outer tubular member 120 and be a self-expanding assemblylike the one shown in FIGS. 1-2. In such a case, the proximal end 110 ofthe strut assembly 104 can be rotatably attached to the guide wire 118with the distal end 112 being slidably mounted on the guide wire toallow for longitudinal motion and rotational motion about the guide wire118.

[0094] The filter element 106 utilized in conjunction with thisparticular embodiment, or which can be utilized with any of the otherembodiments disclosed herein, has a unique shape to provide a largereservoir to collect and maintain any embolic debris which may betrapped within the filter 106. Referring now to FIGS. 9-12, the varioussections of the filter element 106 will be described in greater detail.It should be noted that the filter element 122 of FIG. 22 incorporatesmany of the same filter sections as the filter element 106 shown inFIGS. 10-12. Therefore, corresponding sections of these filters will bedescribed simultaneously in order to better understand the principlesunderlying these unique filter elements. Both filter elements include aproximal cone section 124 which expands to fit within the diameter ofthe artery. This particular proximal cone section 124 blocks or funnelsblood flow and embolic debris into the main or central filter 126. Inboth of the filter elements shown in FIGS. 9 and 22, the proximal conesection 124 includes a plurality of openings 128 which are utilized infiltering the embolic debris. However, it is possible to eliminate theopenings 128 on the proximal cone section 124 to allow it to primarilydirect blood flow and embolic debris directly into the central filter126. This central filter 126 is integral with the proximal cone section124 and includes a number of openings 128 utilized to permit blood flowthrough this section of the filter but to retain any embolic debriswhich is larger than the size of the openings 128. The openings 128 canbe laser cut or otherwise punched into this central filter 126. Thiscentral filter 126 has a substantially cylindrical shape and acts as alarge reservoir for holding the embolic debris. Ideally, it is sizedsuch that when it is completely full of embolic material, it does notcollapse to a smaller profile. However, is should be able to bewithdrawn into the guiding catheter (not shown) when in its fullyexpanded condition with embolic debris trapped therein. Thus, themaximum outer expanded diameter of this central filter 126 should besmaller than the inner diameter of the guiding or sheath utilized indeploying the embolic protection device 100 in the patient'svasculature. The central filter can be made from a stiffer polymericmaterial which will maintain the shape and outer diameter to prevent thefilter from collapsing after use. The resulting stiffer central filtercannot be squeezed during the collapse and removal of the filteringassembly from the artery which should prevent any trapped embolic debrisfrom being squeezed out of the reservoir portion of the central filter.

[0095] Both filters 106 and 122 include a distal tapered region 130which tapers down to the shaft of the guide wire 118. The taper of thisparticular region of the filter elements 106 and 122 facilitates thedelivery of the embolic protection device 100 and helps prevent the“snow plow” effect when being delivered through the patient'svasculature. There is a small distal section 132 which also forms a partof the filter element and is utilized to attach the distal end of thefilter directly onto the guide wire. This distal section 132 can befastened utilizing well-known adhesives or other bonding techniques topermanently affix it to the guide wire 118 and prevent any embolicdebris from escaping through the distal opening of this distal section132.

[0096] The primary benefit of utilizing a large central filter with aproximal cone section is that there is a large filtering area providedby the central filter 126 which is less likely to squeeze out trappedembolic debris when the embolic protection device 100 is being removedfrom the patient's vasculature. As can be seen in FIG. 22, the centralfilter 126 has a general cylindrical shape while the central filter 126of FIG. 9 can be a generally cylindrically shaped but can also includeside creases 134 which produce a unique-looking design. The particularcross-sectional view of the central filter 126 of filter element 106 isshown in FIG. 16 and shows just one of a number of different shapes thatcan be used to create the central filter 126. In use, the filter element122 of FIG. 22 would be attached to the strut assembly 104 and guidewire 118 utilizing adhesives or other bonding techniques.

[0097] The filter element 106 of FIG. 9 also incorporates some uniquefeatures which are not shown in the more basic filter design shown inFIG. 22. These advantages include the unique cross-sectional shape ofthe central filter 126 shown in FIG. 16, along with other features whichhelp maintain the filter element 106 securely attached to the struts 108of the strut assembly 104. Referring again to FIGS. 10-12, the filterelement 106 includes a short outer rim 136 which is proximal to the endof the cone section 124 and has a large inlet opening 125 for receivingthe blood flow and any embolic debris released into the bloodstream.This proximal outer rim 136 is ring-shaped and can be utilized to helpattach the filter onto the struts 108 of the assembly 104. As can beseen in FIG. 10, this proximal outer ring is attached to the middlesection 138 of each strut 108 and includes a tab 123 which can bewrapped around and attached to the strut 108. This proximal outer ring136 also helps maintain the circular inlet opening 125 which must beexpanded and maintained within the artery of the patient. Attached tothe front of the outer rim 136 are restraining straps 142 which arelikewise utilized to help hold the filter onto the struts 108 of theassembly 104. Each restraining strap 142 includes tab-like projections144 which can wrap around each individual strut and be affixed theretoutilizing a bonding agent such as adhesive. These elements allow therestraining straps 142 to hold the filter element 106 onto the strutassembly 104. It should be appreciated that any number of differenttab-like projections 144 can be utilized in conjunction with theserestraining straps 142 to help secure the filter onto the assembly 104.The proximal end of each restraining strap 144 is attached to a sleeve146 which also can be adhesively fixed to the tubular segment 114 formedat the proximal end 110 of the strut assembly 104. These varioussections of the filter 106 can be made as one composite unit and can beformed by cutting a pattern into a pre-formed filter blank. Thereafter,the openings 128 along the length of the filter element 106 can beplaced accordingly.

[0098] The proximal cone section 126 of the filter element 106 shown inFIG. 9 includes a plurality of indented flaps 148 which are utilized tohelp close the opening of the central filter 126 when the proximal cone124 is in its collapsed position. Each of these indented flaps 148, asshown in FIGS. 11, 17 and 18, are created such that as the proximal conesection 124 is being closed, the flaps join together and cooperate toform a barrier which prevents embolic debris from being released throughthe inlet opening 127 of the central filter 126. In the particularembodiment shown in FIG. 9, four such indented flaps can be utilized(only two of which are shown in FIGS. 11, 17 and 18) in order to createthe barrier necessary to close the opening to the central filter 126.However, the number of indented flaps 148 and the size and shape of eachflap 148 can be varied accordingly in order to create a protectivebarrier which helps prevent trapped embolic debris from escaping fromthe central filter 126 as the device 100 is being collapsed for removalfrom the patient.

[0099] Referring now to the FIGS. 19, 20 and 21, a variation of theindented flaps 148 is shown in the proximal cone section 124 of thefilter element 106. As can be seen in these figures, there are a pair offlap portions 150 which are located within the proximal cone section 124and are utilized as a mechanism for closing the inlet opening 127 of thefilter element 106 when the filter assembly is collapsed. These flapportions 150 act much like the indented flaps 148 in that as theproximal cone section 124 is being collapsed, these flap portions 150extend across the inlet opening 127 of the filter element 106 to createa barrier which helps prevent trapped embolic debris from being releasedback into the bloodstream. These flap portions 150 can be smallappropriately shaped pieces which extend across the inlet opening whenthe filter is expanded but do not interfere with the flow of blood goinginto the filter element 106. Blood simply travels around the flapportions 150, along with any embolic debris, to the center filter 126where the embolic debris will be trapped in the debris reservoir. Thisfeature provides a preventive measure to diminish the possible releaseof trapped embolic debris when the embolic protection device 100 isbeing collapsed and removed from the patient's vasculature.

[0100] Referring now to FIGS. 14 and 15, an alternative form of therestraining straps and tabs which are utilized to affix the filterelement 106 is shown. In these particular figures, the restraining strap152 extends along each strut 108 and a tab like projection 154 isutilized to affix the restraining strap to each individual strut 108.Additional lateral strapping members 156 which extend laterally fromeach restraining strap 152 can also be utilized to help prevent thefilter element 106 from moving off the strut assembly 104 during usage.These various designs shows alternative ways of affixing the filterelement 106 onto the strut assembly 104. It should be appreciated thatstill other forms of attaching the filter element 106 to the strutassembly 104 can be utilized without departing from the spirit and scopeof the present invention.

[0101] Another preferred embodiment of the present invention is shown inFIGS. 23 and 24. In this particular embodiment, the embolic protectiondevice 200 includes a filter assembly 202 having a strut assembly 204and a filter element 206. The strut assembly 204 is similar to the strutassembly shown in FIGS. 1-4. It includes self-expanding struts 208 whichare expandable from a collapsed position to a fully expanded position.This strut assembly 204 includes a proximal end 210 and a distal end212. This strut assembly 204 can be made from a piece of tubing in whichthe struts are created by selectively removing portions of the tubing.In this particular embodiment, the tubing can be hypotubing made from ashape memory material such as nickel-titanium (NiTi). The resultingstrut assembly 204 is normally biased to remain in the expanded positionand require the applications of force on the ends 210 and 212 to deploythe struts 208 back to their collapsed position.

[0102] The proximal end 210 includes a segment of tubing 214 and thedistal end 212 includes a similar segment of tubing 216 as well. Thedistal end 212 is permanently attached to the guide wire 218 near thedistal coil 220 of the guide wire. The distal end 212 can be bondedusing adhesives or welded, brazed or soldered to the guide wire 218.Likewise, the proximal end 210 of the strut assembly 204 can be bonded,welded, brazed or soldered to an elongated outer tubular member 222which has a proximal end which extends outside of the patient. Theproximal ends of the elongated tubular member 222 and the guide wire 218can be manipulated by the physician to either open or close the filterassembly 202. A suitable locking mechanism 600 for maintaining the strutassembly 204 in its collapsed or closed position is disclosed in FIGS.43 and 44 and is described in greater detail below.

[0103] The filter element 206 comprises of a cone shape portion 224which is attached to the center section 226 of each strut 208. Aplurality of openings 228 are laser cut or otherwise formed in thefilter 206 which allows blood to flow through the filter but capturesembolic debris which is larger than the size of the openings. This isanother more example of a variation of the embolic protection devicewhich can be made in accordance with the present invention.

[0104] Another embodiment of the present invention is shown as a embolicprotection device 300 in FIGS. 25-28. Like the other embodiments, thisdevice 300 includes a filtering assembly 302 which has an expandablestrut assembly 304 and a filter element 306 attached to the strutassembly 304. Individual struts 308 are formed on the strut assembly 304for moving the filtering element 306 into an expanded position withinthe patient's vasculature. The strut assembly 304 is some what similarsimilar to the previous embodiments disclosed above in that an outerelongated tubular member 310 is utilized in conjunction with a guidewire 312 to collapse and deploy the strut assembly 304. Although notshown in FIGS. 25 and 26, the outer tubular member 310 has a proximalend which extends with the proximal end of the guide wire outside of thepatient to allow the physician to move the proximal ends to deploy orcollapse the filtering assembly 302. The strut assembly 304 can beformed by selectively removing material from the outer tubular member310 near its distal end to create the individual struts 308. The strutswill open upon application of an inward force on ends of the individualstruts 308. Alternatively, the strut assembly 304 can be made from apiece of hypotubing which can be affixed to the outer tubular member 310as is shown in some of the previous embodiments of the invention. Theentire outer tubular member 310 with the strut assembly 304 is free toslide along the length of the guide wire 312 which allows the filteringassembly 302 to be positioned within the patient's vasculature in anover-the-wire fashion.

[0105] As can be seen in FIGS. 25-28, a stop element 320 is located nearthe distal coil 322 of the guide wire 312. This distal stop element 320is utilized in conjunction with the outer tubular member 310 to producethe force necessary to expand the struts 308 into the expanded position.The embolic protection device 300 can be utilized in the followingmatter. First, the physician maneuvers the guide wire 312 into positionpast the lesion or area of treatment. Thereafter, the outer tubularmember 310 with the strut assembly 304 is advanced over the guide wire312 in an over-the-wire technique. The embolic protection device 300remains in its collapsed position while being delivered over the guidewire 312 to the distal end 313 of the guide wire, as is shown in FIG.27. Thereafter, the physician allows the distal sleeve 312 of the outertubular member 310 to contact the stop element 320 located on the guidewire 312. By applying additional force at the proximal end of theelongated tubular member 310, the physician will cause the struts 308 toexpand radially outward for deployment within the artery. The resultingexpansion of the struts 308 thereby opens up the filter element 306within the artery. The physician can then deliver interventional debrisinto the area of treatment and perform the procedure on the lesion. Anyembolic debris which may be created during the interventional procedurewill be collected within the interior of the filter 306.

[0106] A simple locking mechanism 600 device located at the proximal endof the outer tubular member and guide wire, as is shown in FIGS. 43 and44, can be utilized to move and maintain the strut assembly 304 in theexpanded condition. Thereafter, once the embolic protection device 300is desired to be removed from the vasculature, the physician merelyretracts the proximal end of the outer tubular member 310 to remove theforce on the strut assembly 304 allowing the struts 308 to move back tothe collapsed position. Thereafter, the embolic protection device 300and guide wire 312 can be removed from the patient's vasculature.

[0107] The filter element 306 takes on a some what different shape fromthe previous filter element in that the main portion of the filterelement 306 has a shape of a half of a dilatation balloon utilized inangioplasty procedures. Perfusion openings 313 are located on the filterelements 306 for allowing blood perfusion while capturing embolicdebris. The proximal end of the filter element 306 includes a pluralityof restraining straps 314 which extend to a proximal sleeve 316 which isaffixed to the outer tubular member 310 proximal of the struts 308. Thedistal end 318 of the filter element 306 is also attached to the distalsleeve 321 which is formed on the outer tubular member 310 when thestruts 308 are formed.

[0108]FIGS. 29 and 30 show another embodiment of a embolic protectiondevice 400 made in accordance with the present invention. Thisparticular embodiment is somewhat similar to the previous embodiments inthat an external force is generated on the ends of the struts of thestrut assembly to facilitate the outward expansion and inwardcontraction of the struts. Referring specifically now to FIG. 29, theembolic protection device 400 includes a filter assembly 402 having astrut assembly 404 which has a filter element 406 attached thereto. Theindividual struts 408 are formed on an outer tubular member 410 whichhas a distal end 412 attached to the distal end 413 of an inner tubularmember 414. Both the inner member 414 and the outer member 410 haveproximal ends which are located outside of the patient's vasculature.The struts 408 are radially expanded by moving the outer tubular member410 relative to the inner tubular member 414 to apply the necessaryaxial force to cause the struts to deploy outward. An opposite axialforce is necessary to cause the struts 408 to move back to the collapsedposition when the device is to be removed from the patient'svasculature. In this embodiment, more than four struts 408 are used toexpand the filter element 406 within the artery 420. Again, the number,size and shape of the struts 408 can be varied without departing fromthe spirit and scope of the present invention.

[0109] The filter element 406 also has the shape of one half of adilatation balloon utilized in angioplasty procedures and includesopenings 416 which allows blood to flow through the filter but capturesthe desired size of the embolic debris. The proximal end of the filterelement 406 which includes an inlet opening 417 is attached to each ofthe center sections 418 of the struts 408. The distal end 420 of thefilter 406 is attached to the distal end 412 of the strut assembly 404.

[0110] The lumen 422 of the inner tubular member 414 can be utilized fora number of purposes, such as blood perfusion past the deployed filterassembly 402 when placed in the artery. Therefore, should the openings416 of the filter element 406 become clogged with debris which preventsblood from flowing through the filter, oxygenated blood can be perfusedto downstream vessels via the inner lumen of the inner tubular member414. This lumen can also be utilized for delivering the embolicprotection device 404 over a guide wire in an over-the-wire fashion.

[0111]FIGS. 31 and 32 show a variation of the previous filter elementwhich can be utilized in conjunction with the present invention. Thefilter embolic protection device 400 is basically the same device shownin FIGS. 29 and 30 except that-the filter element 430 has a differentdesign. As can be seen in FIG. 31, the filter element 430 includes aproximal cone shape portion 431 which extends in front of the inletopening 432 of the filter element 430. This type of filter 430 hasadvantages in that it may be easier to attach to the strut assembly 404.Additionally, the wall of the artery is insulated from the struts 408 byrestraining straps 434. This device also has the benefits of being lowprofile and allows the use of any guide wire, as well as allowing forguide wire exchanges. This particular embodiment, like the previousembodiments, allows for the exchange of the interventional device in anover-the-wire procedure.

[0112] Referring now to FIGS. 33-38, two different embodiments of thepresent invention are shown which utilize a different mechanism fordeploying the struts of the strut assembly. In FIG. 33, an embolicprotection device 500 is shown as including a filter assembly 502 havingan expandable strut assembly 504 and a filter element 506. As with theother embodiments, the strut assembly 504 includes a plurality ofradially expandable struts 508 which are utilized to place the filterelement 506 into an expanded position within the patient's vasculature.The mechanism for deploying the radially expandable struts 508 utilizesa number of self-expanding deployment members 510 which are attached toeach of the struts 508 making up the expandable strut assembly 504. Theself-expanding deployment members 510 are made from self-expandingmaterials, such as nickel-titanium alloy, which can be compressed to avery small profile and expanded to a rather large expanded positionwhich moves the struts 508 and filter 506 to the fully expandedposition. As is seen in FIGS. 33 and 34, there are a number ofdeployment members 510 which are located along the length of each of thestruts 508. There is a proximal set 512 of deployment members 510located along the proximal region of each strut 508. There is a centerset 514 of deployment members 510 located at the center section of eachstent 508. As can be seen in FIG. 34, the coverage of the filter element506 begins at this center set 514. A third or distal set 516 ofdeployment members 510 is located on the struts in the region where thefilter element 506 is placed to enhance the deployment of each strut.

[0113] As can be seen in FIG. 37, each deployment member 510 isbasically a collapsible piece of self-expanding material which willexpand to a final size when fully deployed. FIG. 38 shows an end view ofthe center set 514 and distal set 516 of the deployment members as theyare located along the struts 508. Each of the sets of deployment members510 will fully expand to a quarter-circle segment which cooperate toform a “ring” when the sets of the deployment members are fullyexpanded. As a result of using this particular construction, the filterelement 506 will fully deploy and maintain a circular-shaped opening 507which will contact the wall of the artery when the embolic protectiondevice 500 is deployed within the patient's vasculature.

[0114] In the first embodiment of this particular embolic protectiondevice 500, the distal end 518 of the expandable strut assembly 504 ispermanently attached to the guide wire 520. The proximal end 522 of thestrut assembly 504 is, in turn, attached to an elongated outer tubularmember 524 which has a proximal end (not shown) which extends outside ofthe patient's vasculature along with the proximal end of the guide wire.The embolic protection device 500 can be moved into its collapsedposition as shown in FIG. 35 by simply retracting the proximal end ofthe outer tubular member 524 to impart an outward force on the ends ofthe strut assembly 504. The force which will be imparted on the ends ofthe strut assembly 504 should be sufficient to collapse each deploymentmembers 510 which will, in turn, cause each of the struts 508 to moveback to the collapsed position. As with the other embodiments, once thestruts 508 are placed in its collapsed position, the filter element 506will likewise collapse and will trap and encapsulate any embolic debriswhich may have been trapped within the filter element 506.

[0115] Referring now to FIG. 36, an alternative embodiment of an embolicprotection device similar to the one shown in FIG. 33 is disclosed. Thisparticular embolic protection device 530 utilized the same filterassembly 502 and strut assembly 504 as shown in the previous embodiment.The differences between the strut assembly 532 of the embolic protectiondevice 530 includes the elimination of the proximal set 512 ofdeployment members 510 from this strut assembly 532. Otherwise, thefilter assembly 534 is virtually the same as the filter assembly 502 ofthe previous device 500.

[0116] The distal end 518 of the strut assembly 534 is also permanentlyaffixed to the guide wire 520 in this particular embodiment. Theproximal end of this particular strut assembly 534 is free to movelongitudinally along the length of the guide wire when being moved froma deployed to a contracted position and visa versa. The mechanism fordeploying the filter assembly 532 is restraining sheath 536 which placesa force on the and deployment members 510 which prevent them fromexpanding until the restraining sheath 536 is retracted. Once theembolic protection device 530 is properly in place within the patient'svasculature, the proximal end (not shown) of the restraining sheath 536is retracted to allow the deployment members 510 to open the struts 508and filter element 506 to the fully expanded position within the artery.When the device is to be removed from the patient's vasculature, therestraining sheath 536 is placed against the proximal region 535 of thestruts 508 and is retracted over the struts to force the deploymentmembers 510 back into their collapsed position. Thereafter, any embolicdebris which may be trapped within the filter element 506 is retainedand safely removed from the patient's vasculature. A proximal set ofdeployment members 510 may not have to be used with this particularembodiment since there may be a need to reduce the amount of expansiveforce applied to the struts in this proximal region 535. However, it isstill possible to place a first set of deployment members at thisproximal region 535 provided that the sheath has sufficient strength tocollapse the struts in this region.

[0117] The filter element 506 shown in FIGS. 33-38 is made from a meshmaterial which allows blood to perfuse therethrough but captures embolicmaterial. The mesh material can be made from any interwoven fabric whichcontains small size openings which will trap the desired size of emboli.Alternatively, the filter 506 can be made from a polymeric material withperfusion openings found therein.

[0118] Referring now to FIGS. 39A, 39B and 40, an alternative strutassembly 550 which could be utilized in conjunction with any of thefiltering assemblies made in accordance with the present invention isshown. The strut assembly 550 includes struts 552 and a deploymentmember 554 which is used to expand the struts 552 into the deployedexpanded position. This deployment member 554 acts in the same manner asthe previously described deployment members in that the deploymentmember 554 can be made from a self-expanding material which will expandto a final size once fully deployed. The deployment member 554 alsocould be collapsed to an unexpanded position when an external force isplaced on the assembly to maintain the deployment member 554 in itscollapsed position. As can be seen in FIGS. 39A, 39B and 40, thedeployment member 554 has a serpentine pattern made of peaks 556 andvalleys 558 which are accordingly attached to the struts 552 of theassembly 550. In these particular embodiment of the invention, thedeployment member 554 has a sinusoidal wave pattern which includes thepeaks 556 and valleys 558 that are attached to the ends of the struts552. This particular pattern allows the struts to be offset or staggeredfrom one another to allow the assembly 550 to be collapsed to a lowerprofile which enhances the assembly's ability to reach tighter lesionsand to be maneuvered into even distal anatomy. The staggered strutdesign also increases the assembly's flexibility which enhances theability to move the assembly within the patient's anatomy. A filterelement could be likewise placed over or within the struts 552 to createa composite filter assembly. The deployment member 554 provides completevessel wall opposition, forcing a seal of the filter edge to the wall ofthe vessel. The deployment member 554 can have multiple geometrieswithout departing from the spirit and scope of the present invention.This particular strut assembly 550 also could be created from a lazedhypotube which incorporates the staggered strut design. The number ofstruts can be varied along with the particular lengths of the struts.Alternatively, the deployment member 554 could be made from a separatepiece of material from the struts and could be attached using methodssuch as soldering, brazing or bonding, using suitable adhesives. As canbe seen from FIGS. 39A and 39B, the attachment of the struts 552 to thepeaks 556 and valleys 558 of the deployment 554 can be varied as shown.Both of these particular designs allow the strut assembly to becollapsed to a low profile.

[0119] Referring now to FIGS. 41 and 42, an alternative filter element570 with an angulated filter edge 572 is shown which is used to help inthe loading and retrieval of the embolic protection device into arestraining sheath. The filter element 570 is similar to the filterspreviously described in that the filter element 570 includes a centralsection 574 which has a plurality of openings 576 that are utilized infiltering the embolic debris. The filter element 570 includes an edge572 which is configured similar to a crown, with pointed peaks 578 andvalleys 580. This configuration of the filter edge 572 allows the filterto be incrementally introduced into the restraining sheath, thuspreventing the material from entering the sheath all at once. As can beseen in FIGS. 41 and 42, the edge 572 has a somewhat sinusoidalconfiguration which would reduce the stress concentration in the valleyregions 580 of the filter. The peaks 578 of the filtering element 570would be matched up with the struts 582 of the strut assembly 584. Thenumber of peaks 578 could vary with the number of struts 582 on thestrut assembly 584. In this particular embodiment, the filtering element570 could be placed within the inside of the strut assembly 584, or,alternatively, the filter could be placed on the outside of the assembly584. It should be appreciated that other filter elements describedherein also could either replace on the inside or outside of the strutassembly used in connection with a particular filtering assembly. As thestrut assembly 584 is being loaded or retrieved, the peaks 578 of thefilter element 570 would enter the restraining sheath first. Thisprevents all of the filtering material from entering the sheath at once,causing a gradual and incremental loading of the filter element 570 intothe sheath. Additionally, dimensions A and B shown in FIG. 42 show thedifference in the valley depths in the sinusoidal pattern of the filteredge 572. This allows for a variety of configurations. One possibleconfiguration is A=B=0. Additionally, B≧A≧0 so that the loading of thefilter into the sheath will be in a smooth operation. This particularconfiguration eliminates or virtually eliminates all of the valleyportions 580 from entering the sheath at the same time. The filter edge572 may or may not have openings 576. The peaks 578 can also havevarying heights. Dimensions C, D and E shown in FIG. 42 shows adifference in the peak heights on the sinusoidal pattern of the filteredge 572. This particular pattern also allows for a variety ofconfigurations. One possible configuration is C=D=E=0. Additionally,E≧D≧C≧0 to correspond, or alternatively, not to correspond with thedepths of the valleys 580.

[0120] Referring now to FIGS. 45-48, an alternative embodiment of anembolic protection device 640 is disclosed. This particular embolicprotection device 640 utilizes a filter assembly 642 and strut assembly644 which is somewhat similar to the strut assembly 550 shown in FIG.39B. The particular strut assembly 644 includes a set of proximal struts646 attached to a deployment member 648 which moves between anunexpanded or collapsed position and an expanded position in the samemanner as the previously described deployment members. This deploymentmember 648 can be made from a self-expanding material which will expandto a final diameter once fully deployed. This deployment member 648 iscollapsible when a sheath or sleeve is placed over the assembly. A setof distal struts 650 are attached to the deployment member 648 and alsoare expandable and collapsible with the deployment member 648. Thedeployment member 648 has a substantial V-shaped wave pattern whichpermits the strut assembly to more easily collapse to a low profile. Afilter element 652 is attached to the strut assembly 644 and has a shapemuch like the filter element 570 shown in FIGS. 41 and 42. The filterelement 652 includes an edge portion 654 which is configured withalternating peaks 656 and valleys 658. This configuration of the filteredge portion 654 also allows the filter to be incrementally introducedinto the restraining sheath 660, thus preventing the filtering materialfrom entering the sheath 660 all at once. As can be seen in FIGS. 45 and46, the filter element of 652 has a somewhat tulip-like shape due to theconstruction of the peaks 656 and valleys 658. As is shown in FIG. 46,the peaks 656 of the filter element 652 are matched up with the wavepattern of the deployment member 648 and are attached thereto usingadhesives or other bonding techniques. The filter can extend along andoutside the struts with the edge portion 654 adhesively attached to theinside edge of the deployment member 648.

[0121] The filter element 652 can be made from a mesh material whichallows blood to profuse therethrough but captures embolic material. Themesh material can be made from interwoven fabric which contains smallsize openings which would trap the desired size of emboli.Alternatively, the filter elements 652 can be made from a polymericmaterial with profusion openings formed therein.

[0122] In this particular embodiment of the embolic protection device640, an obturator 662 is located at the distal end 664 of the filterassembly 642 and is utilized for obtaining smooth deployment through thepatient's vasculature. This particular obturator 662 acts much like thesphere 56 shown in FIGS. 1 and 2 which prevents “snow plowing” of theembolic protection device as it is being delivered through the patient'sarteries. This obturator 662 also has a smooth surface which tapers froma smaller diameter distally to a larger diameter that corresponds to theouter diameter of the restraining sheath 660. A smooth outer surface iscreated when the obturator 662 and restraining sheath 660 are placedadjacent to each other. This obturator can be made from a material suchas PEBAX 40D, or other polymeric materials or alloys which are capableof performing the desired function.

[0123] As is shown in the cross-sectional view of the device in FIG. 48,the obturator 660 is attached (via adhesive or other bonding material)to a tubular member 666, which is made from a material such as polyimidtubing. This tubular member 666 is adhesively or otherwise attached tothe distal ends 668 of the distal struts 650. The tubular member 666 isnot, however, adhesively attached to the guide wire 672, but rather, isallowed to rotate free around the coils 670. The obturator 662 alsoextends over a portion of the coils 670 of the guide wire 672 and isfree to rotate about the coils 670. The proximal end 674 of the filterassembly 642 is attached to the guide wire 672 in such a manner to allowit to rotate freely about or “spin” on the guide wire 672 as well. Thefilter assembly 642 is attached to the guide wire 672 much like theembodiment shown in FIGS. 1 and 2. As can be seen in FIGS. 46 and 48, astop fitting 676 is attached to the guide wire 672 to prevent theproximal end 674 from moving past that particular fitting. A second stopfitting 678, located within the filter assembly 642, helps prevent thefilter assembly 642 from moving axially any substantial distance alongthe guide wire 672.

[0124] The proximal ends 680 of the proximal struts 646 are attached toa pair of tubular segments 682 and 684 which are in a coaxialrelationship. A marker band (not shown) can be partially sandwichedbetween these two tubular segments 682 and 684 to provide the physicianwith a reference when placing the embolic protection device 640 in thepatient's vasculature. The tubular segments 682 and 684 are adhesivelyaffixed to each other and the marker band to form a composite tubularextension member 686. This composite tubular extension member 686extends between the two stop fittings 676 and 678. The extension member686 may include a dampening element 679 which is formed on a portion ofthe segment to help dampen some of the vibratory motion which may betransmitted along the guide wire 672. It can be cut into the extensionmember 686 much like the dampening element 38 is cut on the embodimentshown in FIGS. 1-3. It should be appreciated that this extension member686 can be formed from a single piece of tubing and need not be twoseparately formed segments glued together. This extension member 686also helps to increase the torque response of the embolic protectiondevice 640 on the guide wire and allows more room for the filterassembly to rotate, if needed.

[0125] Additional marker bands 688 can be placed on the strut assembly644 to provide additional reference sources for the physician to rely onwhen maneuvering the device in the patient's arteries. Like thepreviously described filter assemblies, this particular filter assembly642 will remain in place within the patient's vasculature, once deployedtherein, and will remain stationary even if the guide wire 672 isrotated by the physician during an exchange of interventional devicesalong the guide wire. As a result, there is less chance of trauma to thepatient's artery at the location where the filter assembly 642 contactsthe wall of the artery.

[0126] The particular configuration of the filter assembly 640 and itsattachment to the guide wire 672 allows the physician to eliminate anyair bubbles which may be trapped within the restraining sheath 660 as itcovers the filter assembly 642 in its collapsed state. The presentdesign allows the physician to flush a solution, such as saline, throughthe lumen of the restraining sheath 660 out to its distal end to causeany trapped air bubbles to be vented through the distal opening 661 ofthe obturator 662. As a result, the possibility that an air bubblepossibly could be released into the patient's artery can be virtuallyeliminated by thoroughly flushing saline through the restraining sheath660 to eliminate any trapped air bubbles. The tubular member 666 acts asa conduit for the saline to flow out of the obturator 662. Fluid isallowed to flow through the restraining sheath 660 through the innerlumen 688 of the tubular member 666 and out the distal opening 661 ofthe obturator 662.

[0127] Referring now to FIGS. 49 and 50, another alternative embodimentof a embolic protection device 690 is shown. In this particularembodiment, the filter assembly 692 includes a strut assembly 694 whichincludes only a proximal set of struts 696 that are attached to adeployment member 698. This particular filter assembly 692 is somewhatsimilar to the assembly shown in FIGS. 45-48, except that a distal setof struts are not utilized. The filter element 700 is attached directlyto the deployment member 698 and has a distal end 702 which is attachedto a segment of tubing 704. This tubing 704 extends from the proximalend 706 of the filter assembly 692 to the distal end 702 of the filter700 and is rotatable on the guide wire 710.

[0128] In this particular embodiment, the proximal end 706 of the filterassembly 692 is attached directly to a tubing member 704. The proximal706 of the filter assembly 692 terminates in a collar 708 as is shown inFIGS. 49 and 50. It is attached to the tubing 704 using adhesives orother bonding techniques. This entire filter assembly 692, whichincludes the tubing member 704, is rotatable upon the guide wire 710 toallow the device to remain stationary within the patient's artery evenif the guide wire is rotated by the physician during a device exchange.A stop fitting 712 located on the guide wire 710 acts to prevent thefilter assembly 692 from moving axially along the length of the guidewire 710. The distal end 714 of tubing member 704 abuts against the mostproximal coil 716 formed on the guide wire 710. In this manner, the coil716 acts as a stop fitting to prevent axial movement of the tubingmember 704 along the guide wire 710.

[0129] The distal end 702 of the filter 700 is attached to the tubingmember 704 using adhesives or other bonding agents. The distal end 702of the filter does not have to be movable axially along the guide wire,as with the previous embodiments, since the filter 700 itself is pliableand will move as the strut assembly 694 moves between its expanded andcollapsed positions. When the strut assembly 694 is moved from itsunexpanded to expanded position, the filter 700 will “stretch” somewhatas the deployment member 698 and struts 696 move outward and somewhataway from the distal end 702 of the filter 700. As with the previousembodiments, a restraining sheath (now shown) is utilized to move thefilter assembly 692 between its expanded and unexpanded positions.

[0130] Referring now to FIGS. 43 and 44, a simple locking mechanism 600for expanding and collapsing the filter assembly described herein areshown. These particular mechanisms are useful whenever the embolicprotection device utilizes an inner shaft member and outer tubularmember for moving the strut assemblies into the expanded or collapsedposition. Referring first to FIG. 43, the proximal end 602 of the outertubular member 604 is shown with a locking mechanism 600 which can beutilized to lock the embolic protection device in either an expanded orunexpanded position. The locking mechanism 600 includes an elongatedslot 606 which is cut into the wall of the outer tubular member 604 andincludes a first locking position 608 and a second locking position 610.The inner shaft member 612, which can be either a solid shaft such as aguide wire or a hollow tubular shaft, has a raised dimple 614 whichmoves within this elongated slot 606. This raised dimple 614 can bemoved into either the first locking position 608 or second lockingposition 610 to either maintain the filter assembly in an expanded orunexpanded position. It should be appreciated that only two lockingpositions are shown on this particular embodiment, however, it ispossible to use a number of different locking positions if the userdesires to have several expanded positions. If the filter assembly isself-expanding, then a removable handle that pushes and pulls the innerand outer members could be used. The handle would push/pull the innerand outer members to hold the assembly closed, then be removed so thatother interventional devices could be passed over the inner tubularmember. Thereafter, the handle could be placed back onto the proximalends of the inner and outer members to collapse and remove the filterassembly.

[0131] The proximal end 602 of the outer tubular member includes a smallsection of knurling 616, as does the inner shaft member 612, whichprovides the physician with a surface to grip when holding andmaneuvering the proximal ends of these devices. The locking mechanism600 can also include a biasing spring 618 located within the inner lumen620 of the outer tubular member 604 for biasing the inner shaft member612 with an outward force which maintain the raised dimple 614 near thefirst locking position 608. This biasing mechanism includes a shoulderregion 621 located at the proximal end of the outer tubular member and acollar 622 located on the inner shaft member 612. The force of thespring 618 again helps to maintain the dimple 614 at or near the firstlocking position 608. Such a mechanism is preferable when the device isdesigned to be maintained in an unexpanded position until it is ready tobe deployed. It may be beneficial to keep the filter assembly in itsunexpanded position until ready for use since it is possible to causedamage to the filter assembly if left in an expanded position. When thefilter assembly is desired to be placed into the deployed or expandedposition, the physician merely grasps the proximal end of the innershaft member and pulls it back until the dimple 614 is placed into thesecond locking position 610. When the strut assembly is made fromelements which are self-expanding, then there may not be a need to havea biasing spring 618 since the struts on the strut assembly will actsomewhat like a biasing spring to maintain the filter assembly in anexpanded position.

[0132] The strut assemblies of the present invention can be made in manyways. However, the preferred method of making the strut assembly is tocut a thin-walled tubular member, such as nickel-titanium hypotube, toremove portions of the tubing in the desired pattern for each strut,leaving relatively untouched the portions of the tubing which are toform each strut. It is preferred to cut the tubing in the desiredpattern by means of a machine-controlled laser.

[0133] The tubing used to make the strut assembly may be made ofsuitable biocompatible material such as stainless steel. The stainlesssteel tube may be alloy-type: 316L SS, Special Chemistry per ASTMF138-92 or ASTM F139-92 grade 2. Special Chemistry of type 316L per ASTMF138-92 or ASTM F139-92 Stainless Steel for Surgical Implants in weightpercent.

[0134] The strut size is usually very small, so the tubing from which itis made must necessarily also have a small diameter. Typically, thetubing has an outer diameter on the order of about 0.020-0.040 inches inthe unexpanded condition. The wall thickness of the tubing is about0.076 mm (0.003-0.006 inches). For strut assemblies implanted in bodylumens, such as PTA applications, the dimensions of the tubing maybecorrespondingly larger. While it is preferred that the strut assembly bemade from laser cut tubing, those skilled in the art will realize thatthe strut assembly can be laser cut from a flat sheet and then rolled upin a cylindrical configuration with the longitudinal edges welded toform a cylindrical member.

[0135] Generally, the hypotube is put in a rotatable collet fixture of amachine-controlled apparatus for positioning the tubing relative to alaser. According to machine-encoded instructions, the tubing is thenrotated and moved longitudinally relative to the laser which is alsomachine-controlled. The laser selectively removes the material from thetubing by ablation and a pattern is cut into the tube. The tube istherefore cut into the discrete pattern of the finished struts. Thestrut assembly can thus be laser cut much like a stent is laser cut.Details on how the tubing can be cut by a laser are found in U.S. Pat.Nos. 5,759,192 (Saunders) and 5,780,807 (Saunders), which have beenassigned to Advanced Cardiovascular Systems, Inc. and are incorporatedherein by reference in their entirely.

[0136] The process of cutting a pattern for the strut assembly into thetubing generally is automated except for loading and unloading thelength of tubing. For example, a pattern can be cut in tubing using aCNC-opposing collet fixture for axial rotation of the length of tubing,in conjunction with CNC X/Y table to move the length of tubing axiallyrelative to a machine-controlled laser as described. The entire spacebetween collets can be patterned using the CO₂ or Nd:YAG laser set-up.The program for control of the apparatus is dependent on the particularconfiguration used and the pattern to be ablated in the coding.

[0137] A suitable composition of nickel-titanium which can be used tomanufacture the strut assembly of the present invention is approximately55% nickel and 45% titanium (by weight) with trace amounts of otherelements making up about 0.5% of the composition. The austenitetransformation temperature is between about −15° C. and 0° C. in orderto achieve superelastecity. The austenite temperature is measured by thebend and free recovery tangent method. The upper plateau strength isabout a minimum of 60,000 psi with an ultimate tensile strength of aminimum of about 155,000 psi. The permanent set (after applying 8%strain and unloading), is approximately 0.5%. The breaking elongation isa minimum of 10%. It should be appreciated that other compositions ofnickel-titanium can be utilized, as can other self-expanding alloys, toobtain the same features of a self-expanding stent made in accordancewith the present invention.

[0138] The strut assembly of the present invention can be laser cut froma tube of super-elastic (sometimes called pseudo-elastic)nickel-titanium (Nitinol) whose transformation temperature is below bodytemperature. After the strut pattern is cut into the hypotube, thetubing is expanded and heat treated to be stable at the desired finaldiameter. The heat treatment also controls the transformationtemperature of the strut assembly such that it is super elastic at bodytemperature. The transformation temperature is at or below bodytemperature so that the stent is superelastic at body temperature. Thestrut assembly is usually implanted into the target vessel which issmaller than the diameter if the strut assembly in the expanded positionso that the struts apply a force to the vessel wall to maintain thefilter element in the expanded position.

[0139] The piece of tubular hypotube which can be utilized in accordancewith the present invention to form the strut assemblies can be onecontinuous piece which forms both the outer tubular member and the strutassembly as well. In some of the embodiments disclosed herein, the strutassembly is shown as being made from a short segment of hypotube whichis selectively cut to form the strut patterns. Thereafter, the proximalend of the strut assembly is bonded to, either by adhesives, welding,brazing or soldering to the distal end of the outer tubular member.However, these two separate pieces can be formed from a piece of singletubing in a preferred embodiment of the invention.

[0140] The dampening element which is shown in one of the embodiments ofthe present invention could also be used with any of the otherembodiments disclosed herein. The dampening element could either be cutinto the proximal end of the strut assemblies, as is shown in FIGS. 1and 2, or an alternative dampening element could be attached to thestrut assembly. For example, a separate spring made from a differentmaterial or similar material could be welded, brazed or soldered to theend of the strut assembly. Also, other dampening materials could be usedbesides a helical spring in order to achieve dampening. For example,segment of elastomeric material could be bonded to the strut assembly aswell to act as a “shock absorber” for the system.

[0141] The outer tubular member could be made from various materialssuch as stainless steel, nickel-titanium alloy or materials which havememory. As discussed above, when using a separate outer member attachedto the strut assembly, the distal end can be easily affixed to the strutassembly by known bonding methods. The inner diameter of the outertubular member must of course be comparable to the outer diameter of theinner shaft member to allow the outer tubular member to slide in acoaxial arrangement. The inner shaft member can also be made fromstainless steel, nickel-titanium alloys or shape-memory materials. Inone embodiment, the inner shaft member is shown as a tubular memberwhich has an inner lumen which allows the device to slide over a guidewire in an over-the-wire fashion. Other embodiments show the inner shaftmember as a guide wire or guide wire-like shaft. Generally, when theinner shaft member is utilized as a guide wire, it should include anatraumatic guide wire coil tip to prevent injury to the vessel as theguide wire is being maneuvered through the patient's vasculature. Itshould be appreciated that the coil tip does not have to be placeddirectly next to the filtering assembly in those embodiments whichutilize a guide wire as the inner shaft member. The filtering assemblycould be placed much more proximal to the coil tip to create a short,distal segment of guide wire which may be pre-bent by the physician toaid in steering through the patient's vasculature.

[0142] Again, the tubing or hypotube which could be utilized to createthe strut assembly can be a nickel-titanium alloy, such as Nitinol, orother shape-memory materials. It is also possible to utilize stainlesssteel to form the strut assembly as well. The strut assembly could alsobe made from a self-expanding material even in embodiments in which theouter tubular member and inner shaft member are utilized to provide theaxial forces necessary to expand or contract the device during use.Additionally, the strut assembly could be either biased to remain in itscollapsed position or expanded position as may be desired. It should beappreciated that the stent assembly can be made from either pseudoelastic NiTi stressed induced martensite or shape memory NiTi.

[0143] The polymeric material which can be utilized to create thefiltering element include, but is not limited to, polyurethane andGortex, a commercially available material. Other possible suitablematerials include ePTFE. The material can be elastic or non-elastic. Thewall thickness of the filtering element can be about 0.001-0.005 inches.The wall thickness may vary depending on the particular materialselected. The material can be made into a cone or similarly sized shapeutilizing blow-mold technology. The perfusion openings can be anydifferent shape or size. A laser, a heated rod or other process can beutilized to create to perfusion openings in the filter material. Theholes, would of course be properly sized to catch the particular size ofembolic debris of interest. Holes can be lazed in a spinal pattern withsome similar pattern which will aid in the re-wrapping of the mediaduring closure of the vice. Additionally, the filter material can have a“set” put in it much like the “set” used in dilatation balloons to makethe filter element re-wrap more easily when placed in the collapsedposition.

[0144] The materials which can be utilized for the restraining sheathand recovery sheath can be made from similar polymeric material such ascross-linked HDPE. It can alternatively be made from a material such aspolyolifin which has sufficient strength to hold the compressed strutassembly and has relatively low frictional characteristics to minimizeany friction between the filtering assembly and the sheath. Friction canbe further reduced by applying a coat of silicone lubricant, such asMicroglide®, to the inside surface of the restraining sheath before thesheaths are placed over the filtering assembly.

[0145] In view of the foregoing, it is apparent that the system anddevice of the present invention substantially enhance the safety ofperforming certain interventional procedures by significantly reducingthe risks associated with embolic material being created and releasedinto the patient's bloodstream. Further modifications and improvementsmay additionally be made to the system and method disclosed hereinwithout departing from the scope of the present invention. Accordingly,it is not intended that the invention be limited, except as by theappended claims.

What is claimed:
 1. An embolic protection device for capturing embolicdebris released into a body vessel of a patient, comprising: a shaftmember having distal and proximal ends; and a filtering assemblyrotatably mounted on the shaft member, the filtering assembly includingan expandable strut assembly and a filter attached to the strut assemblyelement for capturing embolic debris, the expandable strut assemblyhaving a first set of struts, each strut having a first and second end;a second set of struts, each strut having a first and second end; and adeployment member movable between a collapsed position and an expandedposition, wherein first end of the first set of struts and the first endof the second set of struts each are attached to the deployment memberat different locations along the deployment member and the set ofexpandable struts are movable between a collapsed position and anexpanded position, the filter element being movable with the struts tothe expanded position so that at least a portion thereof contacts thewall of the vessel to capture embolic debris released into the bodylumen.
 2. The embolic protection device of claim 1, wherein the strutsare self-expanding.
 3. The embolic protection device of claim 1, whereinthe strut assembly has proximal and distal ends, the proximal end beingrotatably affixed to the shaft member and the distal end being movablelongitudinally along the shaft member and being rotatable as well. 4.The embolic protection device of claim 3, wherein the proximal end ismounted between a pair of stop elements which prevent any longitudinalmotion of the proximal end relative to the shaft member while permittingthe filtering assembly to be rotatable on the shaft member.
 5. Theembolic protection device of claim 4, wherein at least one of the stopelements is made from a radiopaque material.
 6. The embolic protectiondevice of claim 1, wherein the strut assembly is made from a segment oftubing which has portions of the tubing selectively removed to form eachof the struts of the assembly.
 7. The embolic protection device of claim6, wherein the segment of tubing is hypotubing made from aself-expanding material.
 8. The embolic protection device of claim 6,wherein the portions of the tubing which are selectively removed areshaped in a desired pattern to form struts having particular size andshape.
 9. The embolic protection device of claim 1, further including adampening element attached to the strut assembly which is adapted to atleast partially absorb vibratory motion which may be transmitted alongthe shaft member and to at least partially isolate such vibratory motionfrom the filtering assembly.
 10. The embolic protection device of claim9, wherein the dampening element is a helical coil.
 11. The embolicprotection device of claim 9, wherein the dampening element is disposedbetween a pair of stop fittings.
 12. The embolic protection device ofclaim 1, wherein the deployment member is self-expanding.
 13. Theembolic protection device of claim 12, wherein the deployment member hasa pattern of alternating peaks and valleys in a wave pattern, each ofthe first ends of the first set of struts being attached to the valleyportions of the deployment member and each of the first ends of thesecond set of struts being attached to the peak portions of thedeployment member.
 14. The embolic protection device of claim 1, whereinthe first set of struts and second set of struts are arranged in astaggered pattern along the deployment member.
 15. The embolicprotection device of claim 1, wherein each of the struts of the firstset are arranged in a staggered pattern with each of the struts of thesecond set of struts along the deployment member.
 16. The embolicprotection device of claim 1, wherein each of the second ends of thefirst and second set of struts are attached to a collar which is movableaxially along the shaft member.
 17. The embolic protection device ofclaim 1, wherein the deployment member is integral with each of thestruts of the first and second sets of struts.
 18. The embolicprotection device of claim 1, wherein the deployment member providesvessel wall opposition.
 19. The embolic protection device of claim 1,wherein the filter element includes a central region having an inletopening and defining a storage reservoir for capturing embolic debris,the central region having a plurality of openings adapted to allow bloodto flow therethrough but capture embolic debris larger than the size ofthe openings and contain the debris within the reservoir; and a filteredge integral with the central region and having an inlet opening, thefilter edge having a pattern of alternating peak and valley regionswhich prevent the filter edge from entering into a restraining sheathall at one time.
 20. The embolic protection device of claim 19, whereinthe filter edge has a wave configuration which includes peak and valleyregions.
 21. The embolic protection device of claim 19, wherein the peakportions are attachable to the deployment member of the strut assembly.22. The embolic protection device of claim 13, wherein the peak andvalley regions have a substantially V-shaped configuration.
 23. Theembolic protection device of claim 1, further including an obturatorattached to the distal end of the filtering assembly which has a taperedconfiguration which facilitates the insertion of the embolic protectiondevice through the body vessels of the patient.
 24. The embolicprotection device of claim 23, further including a restraining sheathwhich is adapted to be placed over the shaft member and filteringassembly in a coaxial arrangement to collapse the expandable strutassembly into its collapsed position.
 25. The embolic protection deviceof claim 24, wherein the obturator and restraining sheath abut againsteach other when the restraining sheath is placed over the filteringassembly for position within the blood vessel of the patient to create acomposite catheter which facilitates the delivery of the embolicprotection device through the body vessels of the patient.
 26. Theembolic protection device of claim 25, wherein the restraining sheathhas a lumen defined therein for receiving fluids for eliminating any airbubbles trapped within the lumen and the obturator.
 27. An embolicprotection device for capturing embolic debris released into a bodyvessel of a patient, comprising: a shaft member having distal andproximal ends; and a filtering assembly rotatably mounted on the shaftmember, the filtering assembly including an expandable strut assemblyand a filter attached to the strut assembly element for capturingembolic debris, the expandable strut assembly having a set of struts,each strut having a first and second end, a deployment member movablebetween a collapsed position and an expanded position, wherein each ofthe first ends of the struts are attached to the deployment member atdifferent locations along the deployment member and the struts aremovable between a collapsed position and an expanded position, thefilter element being movable with the struts and expandable member tothe expanded position so that at least a portion thereof contacts thewall of the vessel to capture embolic debris released into the bodylumen.
 28. The embolic protection device of claim 27, wherein the strutsare self-expanding.
 29. The embolic protection device of claim 28,wherein the proximal end is mounted between a pair of stop elementswhich prevent any longitudinal motion of the proximal end relative tothe shaft member while permitting the filtering assembly to be rotatableon the shaft member.
 30. The embolic protection device of claim 27,wherein the deployment member is self-expanding.
 31. The embolicprotection device of claim 30, wherein the deployment member has apattern of alternating peaks and valleys in a wave pattern, each of thefirst ends of the struts being attached to being attached to the peakportions of the deployment member.
 32. The embolic protection device ofclaim 31, wherein the struts are arranged in a staggered pattern alongthe deployment member.
 33. The embolic protection device of claim 27,wherein the deployment member is integral with each of the struts. 34.The embolic protection device of claim 27, wherein the deployment memberprovides vessel wall opposition.
 35. The embolic protection device ofclaim 27, wherein the filter element includes a central region having aninlet opening and defining a storage reservoir for capturing embolicdebris, the central region having a plurality of openings adapted toallow blood to flow therethrough but capture embolic debris larger thanthe size of the openings and contain the debris within the reservoir;and a filter edge integral with the central region and having an inletopening, the filter edge having a pattern of alternating peak and valleyregions which prevent the filter edge from entering into a restrainingsheath all at one time.
 36. The embolic protection device of claim 35,wherein the filter edge has a wave configuration which includes peak andvalley regions.
 37. The embolic protection device of claim 35, whereinthe peak portions are attachable to the deployment member of the strutassembly.
 38. The embolic protection device of claim 27, furtherincluding a tubular member attached to each of the seconds ends of thestruts and wherein the filter element has a tapered distal end which isattached to the tubular member, the tubular member being rotatablymounted on the shaft member.
 39. The embolic protection device of claim38, wherein the filter element a proximal opening which is attached tothe deployment member.
 40. The embolic protection device of claim 38,wherein the tubular member is disposed between two stop elements locatedon the shaft member.
 41. The embolic protection device of claim 40,wherein the shaft member is a guide wire and one of the stop fittings iscoils forming part of the guide wire.